对称损失下一类刻度分布族参数的估计

q对称熵损失函数L(θ,δ)=θ_q/δ_q+δ_q/θ_q-2(0-νe_-T(x)/θ参数θ的估计, 得到 了θ的最小风险同变(MRE)估计及Bayes估计的一般与精确形式, 并讨论了θ的形如cT(X)+d的一类线性估计的可容许性和不可容许性以及θ的MRE估计的最小最大性.     

一种加权对称损失函数下一类指数分布模型参数的估计

对刻度参数指数分布模型c(x,n)θ-v e-T(x)/θ提出了一种新的损失函数——加权p,q对称熵损失函数L(θ,δ)=θp/pδp +δq/qθq -2(p,q＞O,q＜v),并用它研究了刻度参数θ的估计.得到了参数θ的最小风险同变估计与Bayes估计的一般形式与精确形式,这两种估计形式比已有文献中相应形式更为简捷...     

关于参数矩阵的线性经验Bayes估计

设X为p×q随机矩阵,θ为p×q参数矩阵,且θ有先验分布G(Vec(θ)),给定θ,X有条件密度f(Vec(X)｜Vec(θ)).选取矩阵损失L(D(X),θ)=(D(X)-θ)′(D(X)-θ),并在风险矩阵的迹的大小比较标准下讨论θ的线性经验tr Bayes估计及其渐近性质.获得经验tr Bayes估计D tr(X)= X+U(X- X),及具有o(N-1δ-2N)的渐近收敛速度.     

GBVE-指数模型结构可靠度估计

设二元随机变量(X,Y)的联合生存函数为F(x,y)=exp{-[(x/θ1)1/8+(y/θ2)1/8]8},0＜x,y＜∞,0＜δ≤1,0＜θ1,θ2＜∞,把它称作GBVE (θ1,θ2,δ).考虑串联系统两元件的应力服从GBVE (θ1,θ2,δ),强度服从指数分布的应力一强度模型,分别在应力参数和强度参数未知的...     

PA样本下单边截断型分布族位置参数函数的经验Bayes估计

对单边截断型分布族在同分布正相协(PA)样本下,构造了位置参数函数的经验Bayes(E.B)估计,由分析可知,在适当的条件下,证明了位置参数θ的函数的经验Bayes(E.B)估计的收敛速度为O(n-q),其中,q=λα(δ-2)/(2α 4)δ;α>0;0<λ<δ/(1 δ);δ>2。     

CM分担一个小函数的亚纯函数

研究CM分担小函数的亚纯函数唯一性问题.得到两个唯一性定理:定理1　设f(z)和g(z)是非常数亚纯函数,α(z)和β(z)分别是f(z)和g(z)的小函数.如果δ(∞,f)=δ(∞,g)=1,δ(0,f) δ(0,g)>1,P(f)=α Q(g)=β,则βP(f)≡αQ(g)或P(f)Q(g)≡αβ　　定理2　设f(z)是非常数亚纯函数,α(z)是f(z)的非零小函数,f-α的零点重数为1.如果f=α f′=α,且当λ<1/2时2N(r,f) N(r,1/f′) N(r,1/(f″-α′)) N(r,1/(f′-α′))<λT(r,f)则f′-αf-α≡c (非零常数).     

对数误差平方损失函数和MLINEX损失函数下一类分布族参数的Minimax估计

考虑如下一类分布族:F(x;θ)=1-[g(x)]θ,A≤x≤B,θ＞0,其中g(x)是关于x单调递减的可微函数,且g(A)=1,g(B)=0.在对数误差平方损失函数和MLINEX损失函数下,得到了参数的Bayes估计和Minimax估计.     

（K1，4；2）-图的闭包和周长

针对(K1,4;2)-图这一新的图类,证明了以下结论:1)设G是δ≥5且K1 V P4-free的(K1,4;2)-图,则c(G)=c(cl(G));2)设G是δ≥5且T3-free的(K1,4;2)-图,则c(G)=c(a(G)).     

具有最大亏量和的整函数及其它们的平均值

S.M.Shah和Herb,Silverman得到设f(z)是下级为有限的整函数,满足sum from a≠∞δ(a,f)=1.令M_o(r)=expT(r,f),M_3(r)={1/(2π)integral from n=0 to 2π|f(re~(iθ))|dθ}~(1/3),0相似文献   

复合Linex损失函数下Gamma分布的尺度参数的Bayes估计

在复合Linex对称损失函数下,当Gamma分布Γ（θ,α）的尺度参数θ（形状参数α已知）的先验分布π（θ）服从Gamma 分布Γ（λ,β）时,得到了尺度参数θ的唯一的Bayes估计δB.同时,对尺度参数θ的Bayes估计δB讨论了其可容许性.其结果是：当c=0,d＊＜d＜∞时,估计量δB是可容许估计.     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to